In conventional firearms, either a striker or a hammer and firing pin is provided for detonating percussion primers. Although many advances in conventional firearm design have been made over the years, the underlying principle of ignition by impact is based on technology essentially optimized in the last century. Percussion primers in today's ammunition and the complexity of moving parts in a firearm having a mechanical fire control system are key design constraints in implementing significant improvements in safety, performance and reliability using conventional technology.
The complexity of moving parts in a mechanical fire control system is especially problematic in a handgun having multiple chambers, such as a revolver, in which a cylinder is rotatable about its centerline on a center pin, and pivotable on a yoke in order to insert and remove the cartridges.
Although electronic components have been designed into the ignition systems of firearms, generally the electrical components either supplement or displace existing parts of the mechanical firing mechanism. The percussion primer is still detonated in the conventional manner, e.g., by impact from a firing pin or striker. U.S. Pat. No. 4,793,085 Electronic Firing System for Target Pistol, for example, shows a pistol in which a mechanical trigger bar is displaced by a solenoid. U.S. Pat. No. 5,704,153 Firearm Battery and Control Module describes a firearm incorporating a microprocessor in an ignition system for a firearm using conventional percussion primers.
Electronic safety mechanisms have been developed for use in revolvers as well as pistols, as illustrated in U.S. Pat. No. 4,970,819 Firearm Safety System and Method, in which actuation of the firing mechanism is blocked until a grip pattern sensing means on the handgrip of the firearm provides a signal to a microprocessor that corresponds to a prestored grip pattern. Typically, however, the electronic safety system of the '819 patent adds an additional layer of complexity to the revolver, by blocking but not replacing, the conventional mechanical firing mechanism for firing percussion primers.
Electronics have also been designed into ignition systems for firearms that use non-conventional primers and cartridges. U.S. Patent No. 3,650,174 for Electronic Ignition System for Firearms describes an electronic control system for firing electrically primed ammunition. The electronic control of the '174 patent, however, is hard-wired and lacks the multiple sensor interfaces or the programmable central processing unit that is found with the present invention. U.S. Pat. No. 5,625,972 for a Gun With Electrically Fired Cartridge describes an electrically fired gun in which a heat-sensitive primer is ignited by a voltage induced across a fuse wire extending through the primer. U.S. Pat. No. 5,272,828 for Combined Cartridge Magazine and Power Supply for a Firearm shows a laser ignited primer in which an optically transparent plug or window is centered in the case of the cartridge to permit laser ignition of the primer. Power requirements and availability of fused and/or laser ignited primers are problematic however.
U.S. Pat. No. 5,755,056, for Electronic Firearm and Process for Controlling an Electronic Firearm shows a firearm for firing electrically activated ammunition having a round sensor, and a bolt position sensor. The technology of the '056 patent, however, is limited to a firearm with a bolt action.